Land area requirements for coal: Saskatchewan

 

There are three coal-fired power stations in Saskatchewan: Boundary Dam (672 megawatts) and Shand (276 megawatts) are located in the south-east close to Estevan and a few kilometres from the U.S. border. Poplar River (582 megawatts) is located a similar distance from the U.S. border but in the south-central region close to Coronach.

 

Map Showing Location of Saskatchewan's Three Coal-fired Power Stations

Source: Google maps

 

When considering coal-fired power stations proponents tend to note that coal is a dense source of energy relative to wind. Coal is not strictly the correct term for the material burned at Boundary Dam, Shand and Poplar River. The material is actually Lignite, or 'Brown Coal' as it is known in Germany. Lignite is, from a geological perspective, young and is the least energy dense of the various coal types. In fact it is more akin to peat than coal. 

 
 

Source: Craig Morris (@ppchef)

Due to its young age, lignite is found at shallow depths and consequently is strip-mined (otherwise known as 'surface mining'). In other words the top-soil is scraped off and the lignite removed by vast bucket trucks such as this one in Saxony, Germany.  

The waste ash from the power station, which here in Saskatchewan, includes about 400 hundred tonnes of toxic heavy metals annually, is dumped back into the same location before the top soil is replaced (one hopes) and the soil eventually, after many years, is returned to its initial state (sort of). However the process is slow which means that at any one time there is a significant amount of land 'out of commission'. 

 

Needless to say SaskPower does not produce any information on the amount of land currently used for strip mining (and hence unavailable for other activities). However and due to the wonders of Google and satellites, it is easy to get a reasonably good idea. Included below are satellite photos of Saskatchewan's two strip mined areas.

 

Fig 1. Boundary Dam and Shand Power Stations & Associated Strip Mines

Source: Mapbox

 

Fig 2. Poplar River Power Station
& Mine Site

 

These two satellite images confirm that the physical footprint of the power stations themselves is relatively small. Much  more significant however is the area of land which is taken out of use for strip mining. The strip-mined land is the area in Figures 1 & 2 which is light grey/white and devoid of vegetation (or flooded in the case of Poplar River). 

To give some perspective both images include a scale:
Figure 1 includes a blue line which measures 30 kilometres. As for the green block labelled '7.5 square kilometres': this is the amount of land which would be required to site the wind turbines needed to generate the same amount of electricity as Boundary Dam and Shand (explanation below).

Figure 2 shows the Poplar River power station in the top left corner. The width of land affected is 2.7 kilometres. 

Comparison with Wind and Solar Power

 

Since, as noted, SaskPower does not provide any information on the amount of land employed in coal strip mines - this comparison has, of necessity, to be somewhat subjective. Consequently and since two different sites are involved, we have chosen to focus on the larger one i.e. Figure 1 (Boundary Dam and Shand).

Boundary Dam and Shand have a combined capacity of 948 megawatts (672 +276). Since coal generates electricity with an average capacity factor of 78 percent, this implies that these two power station will generate 6.5 terawatt hours annually or 28 percent of total annual provincial electricity generation.

So how much land would be required to generate the same amount of electricity with wind turbines? 

As we have demonstrated, the amount of land physically occupied by wind turbine infrastructure (roads, substations, turbine foundations etc) and hence which cannot be used for agriculture or other uses, is about 0.4 hectares (1 acre) per megawatt of installed wind capacity.

To generate 6.5 terawatt hours annually using wind energy would require 1,850 megawatts of wind capacity. This would occupy 1,850 * 0.4 = 750 hectares, 7.5 square kilometres or a square of land with dimensions of 2.7 kilometres. Just such a square, in green (what else!) is shown in the top right of Figure 1.

A simple subjective analysis of Figure 1 shows beyond doubt that coal's land use footprint is substantially larger than it is for wind.

Additional benefits of wind energy include the fact that it is half the price of coal with carbon capture and it does not release hundreds of tonnes of  toxic heavy metals to the atmosphere and land each year.

So: wind needs less land, is half the price and generates no atmospheric or landfill pollutants.

Wind or coal: which would you prefer? Tough choice.